Apparatus for feeding, transporting and printing pluralities of individual objects, where the population consists of objects of substantially identical and repeatable size and shape, is known. The pharmaceutical and confectionary industries use such apparatus for conveying individual objects past a printing station for printing indicia, such as a trademark or other identifying information, thereon.
Representative of the prior art are U.S. Pat. Nos. 2,787,786; 2,859,689; 2,931,292; 3,026,792; 3,042,183; 3,200,556; 3,272,118; 3,613,861; 3,739,909; 3,838,766; 3,868,900; 3,871,295; 3,884,143; 3,912,120; 3,917,055; 3,931,884; 4,069,753; and 4,308,942.
Prior art apparatus have used gravity to feed tablets, capsules, candies and the like to rotating transport cylinders. Gravity induced feed as illustrated in U.S. Pat. No. 4,308,942 is typical and has been used heretofore with tablets, pills and capsules having substantially smooth, dry exteriors and having regular shapes, e.g. telescoping capsules, spherical pills and cylindrical tablets.
With the advent of tablets and other solid objects which are odd shaped and/or which do not have substantially smooth, dry exteriors and with the need for ever-higher rates of tablet, capsule, pill and other solid object processing, gravity induced feed no longer provides adequate feed rates and does not provide acceptable fill efficiency in the rotating transport cylinders. Screw conveyors at the bottoms of storage hoppers have been used in an attempt to achieve acceptable feed rates and fill efficiencies and have achieved some measure of improvement. Also, vacuum has been employed to help draw lightweight objects, specifically empty telescoping pharmaceutical capsules, from hoppers to transport cylinders. However, the need remains for even greater feed rates and fill efficiencies and for reliable apparatus filling these needs, particularly in connection with objects which are odd-shaped and/or have smooth, dry exteriors.